In Civ IV I play epic. But I will play my first game of Civ V on normal, with default settings. It's not the same game, so I gotta give a try to the "default" the developers have envisioned. Only then will I adapt it to my taste. Even though there are many hints that the speed issue will be the same as in Civ IV, it's still premature to just go ahead and set it to epic or marathon right away as if this were Civ IV.